Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds useful context beyond them: it is a pure calculation from measured inputs, requires no authentication, and does not read or save account data, plus the domain caveat about measuring under driving conditions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three front-loaded sentences with no wasted wording; the outputs are named first, then the no-auth/no-persistence note, then the measurement caveat. The middle sentence overlaps somewhat with the readOnly annotations, keeping it just short of perfect.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, and the schema fully documents all inputs. For a stateless calculator the description covers purpose, safety posture, and the key measurement precondition, leaving nothing an agent needs to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all five parameters (lf, rf, lr, rr, unitSystem) are already documented with units and the enum. The description only alludes to 'four scale pads', adding no syntax or meaning beyond the schema, which is the expected baseline when the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Calculate') and the exact resources it derives: cross weight, left/right balance, and front/rear split from four scale pads. This distinguishes it from sibling calculators such as calculate_brake_bias or calculate_spring_wheel_rate without needing to open the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives valuable input-preparation guidance ('Measure the car in the same state you drive it: driver, fuel, ballast, and tire pressures matter'), which tells the agent how to use the tool correctly. However, it never states when to choose this tool over alternatives or any exclusions/conditions, so usage is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.